Our aims are: To establish the occurrence and the importance of a newly described lysosomal enzyme that cleaves angiotensin II and other peptides. To explore the identity of kininase II with the angiotensin I converting enzyme and to assess the role of the enzyme under normal and pathological conditions. To develop chemical assays for measuring these enzymes. To couple enzymes that release or inactivate peptides with large molecular weight carriers and to use these insoluble polymers in biological studies. To purify kininase I (carboxypeptidase N).